<template>
  <div class="slideshow">
    <ul class="slideshow-body">
      <li class="slideshow-item" v-for="(item, i) in slides" :key="i" :class="{fade:index===i}" @mouseenter="stop" @mouseleave="start">
        <!-- 图片 -->
        <RouterLink :to="item.hrefUrl" v-if="item.hrefUrl">
          <img
            :src="item.imgUrl"
            alt=""
          />
        </RouterLink>
        <!-- 商品列表 -->
          <div v-else class="slider">
            <RouterLink v-for="goods in item" :key="goods.id" :to="`/product/${goods.id}`">
              <img :src="goods.picture" alt="">
              <p class="name ellipsis">{{goods.name}}</p>
              <p class="price">&yen;{{goods.price}}</p>
            </RouterLink>
          </div>
      </li>
    </ul>
    <a @click="toggle(-1)" href="javascript:;" class="slideshow-btn prev">
      <i class="iconfont icon-angle-left"></i>
    </a>
    <a @click="toggle(1)" href="javascript:;" class="slideshow-btn next">
      <i class="iconfont icon-angle-right"></i>
    </a>
    <div class="slideshow-indicator">
      <!-- active控制显示图片位置点 -->
    <!-- // 4: 点击 下面点 可以切换 -->
      <span @click="index = i" v-for="(item, i) in slides" :key="i" :class="{active:index===i}"></span>
    </div>
  </div>
</template>

<script>
import { onUnmounted, ref, watch } from 'vue'
export default {
  name: 'Slideshow',
  props: {
    slides: {
      type: Array,
      default: () => []
    },
    // 是否自动轮播
    autoPlay: {
      type: Boolean,
      default: false
    },
    // 间隔时长
    duration: {
      type: Number,
      default: 3000
    }
  },
  setup (props) {
    // 控制显示图片索引
    const index = ref(0)
    // 自动轮播逻辑
    // eslint-disable-next-line
    let timer = null
    const autoPlayFn = () => {
      clearInterval(timer)
      // 自动播放
      timer = setInterval(() => {
        index.value++
        if (index.value >= props.slides.length) {
          index.value = 0
        }
      }, props.duration)
    }
    // 1： 需要监听slides的数据变化，判断slides有值且autoPlay为true
    watch(() => props.slides, (newVal) => {
      if (newVal.length && props.autoPlay) {
        autoPlayFn()
      }
    }, { immediate: true })
    // 2: 鼠标进入暂停定时器， 离开开启定时器
    const stop = () => {
      if (timer) {
        clearInterval(timer)
      }
    }
    // 3：鼠标离开
    const start = () => {
      if (props.slides.length && props.autoPlay) autoPlayFn()
    }
    // 4：点击上一张和下一章
    const toggle = (num) => {
      stop()
      if (index.value === 0 && num === -1) {
        index.value = props.slides.length
        // index.value += num
      } else if (index.value === props.slides.length - 1 && num === 1) {
        index.value = -1
      }
      index.value += num
      start()
    }
    // 5: 组件卸载，清除定时器
    onUnmounted(() => {
      clearInterval(timer)
    })
    return {
      index,
      stop,
      start,
      toggle
    }
  }
}
</script>

<style scoped lang="less">
@import '../../assets/styles/variable.less';
.slideshow {
  width: 100%;
  height: 100%;
  min-width: 300px;
  min-height: 150px;
  position: relative;
  .slideshow {
    &-body {
      width: 100%;
      height: 100%;
    }
    &-item {
      width: 100%;
      height: 100%;
      position: absolute;
      left: 0;
      top: 0;
      opacity: 0;
      transition: opacity 0.5s linear;
      &.fade {
        opacity: 1;
        z-index: 1;
      }
      img {
        width: 100%;
        height: 100%;
      }
    }
    &-indicator {
      position: absolute;
      left: 0;
      bottom: 20px;
      z-index: 2;
      width: 100%;
      text-align: center;
      span {
        display: inline-block;
        width: 12px;
        height: 12px;
        background: rgba(0, 0, 0, 0.2);
        border-radius: 50%;
        cursor: pointer;
        ~ span {
          margin-left: 12px;
        }
        &.active {
          background: #fff;
        }
      }
    }
    &-btn {
      width: 44px;
      height: 44px;
      background: rgba(0, 0, 0, 0.2);
      color: #fff;
      border-radius: 50%;
      position: absolute;
      top: 228px;
      z-index: 2;
      text-align: center;
      line-height: 44px;
      opacity: 0;
      transition: all 0.5s;
      &.prev {
        left: 20px;
      }
      &.next {
        right: 20px;
      }
    }
  }
  &:hover {
    .slideshow-btn {
      opacity: 1;
    }
  }
}
// 轮播商品
.slider {
  display: flex;
  justify-content: space-around;
  padding: 0 40px;
  > a {
    width: 240px;
    text-align: center;
    img {
      padding: 20px;
      width: 230px!important;
      height: 230px!important;
    }
    .name {
      font-size: 16px;
      color: #666;
      padding: 0 40px;
    }
    .price {
      font-size: 16px;
      color: @priceColor;
      margin-top: 15px;
    }
  }
}
</style>
